Darwinian theory states that humans evolved on Earth and are consequently adapted to interact with their environment. For example, when exposed to sunlight, human skin synthesizes vitamin D, a useful vitamin. The use of blue light (i.e., the color of the sky), when used in conjunction with an aminolevulinic acid treatment, is documented to improve porphyrin response times in skin.
The human eye is another organ known to react to environmental factors. Phototherapy, or the science of exposing the body to a spectrum of light for therapeutic purposes, is known or believed to be effective in treating Seasonal Affective Disorder, nonseasonal depressions, and delayed sleep phase syndrome when specific types of light are received by the human eye.
The first generation of light therapy devices produced a white light across the spectrum of wavelength, often requiring a source to illuminate at levels of up to 10,000 lux. Such intense light includes ultraviolet and infrared light that can be harmful to the human eye at intense levels. The benefit from these devices is cancelled by these adverse health benefits associated with intense levels of exposure.
Modern studies reveal that certain specific wavelengths of light, often in the blue spectrum ranging from 420 to 485 nm, are most effective in the treatment of Seasonal Affective Disorder and other psychiatric conditions. These benefits have been linked with the capacity of blue light to suppress the naturally present melatonin in the human retina, and more specifically, to interact with the melatonin receptor 1B (MT2 subtype). Melatonin is a primary hormone secreted by the pineal gland. Other research has shown a greater proportion of melatonin in the inferior and/or nasal portion of the retina.
Existing cosmetic devices that seek to expose individuals to light at wavelengths in the blue spectrum are bulky and difficult to manage. In addition, such devices require a power source and are otherwise difficult or impossible to use in a mainstream consumer application. An example of a prior art device is shown in FIG. 1. A selective color filter is placed between a nonportable source of light and a user of the device. Since the effective dose is measured as the incoming flux of radiation multiplied by the exposure time to the radiation, for a constant dose, the time of exposure can only be reduced if the intensity of the light is increased. As a consequence, the benefits of high-intensity light, even in the blue spectrum, is offset by the potential health hazards from intense light exposure.
In addition, most existing light therapy devices make use of an electric power source to generate light. Some models of light enhancement devices include eyewear with battery-powered light emitting diodes (LEDs) or other light sources. An example of this prior art device is shown in FIG. 2. Glasses equipped with bulky equipment are uncomfortable to wear and require frequent regeneration of the power source. While these devices convey the benefits of light therapy in the strictest sense, they do not address the real challenges inherent with the cosmetic and practicality concerns of the wearer.
Yet another type of prior art sunglasses used for light therapy does not use a power source but simply filters and attenuates incoming ambient photons at sunlight spectrum wavelengths. This technology makes use of a filter or a plurality of filters to eliminate or otherwise attenuate part of the incoming light spectrum (often, any non-beneficial wavelengths) from passing through the medium. In short, such technology is subtractive only and does not enhance beneficial wavelengths.
Finally, another type of prior art uses chemically fluorescent material to enhance the sensation of certain specific colors in the visible spectrum by use of a fluorescent dye. As a consequence of dyeing the lens, other colors in the visible radiation spectrum decrease in intensity. A contrast is created and some colors that cannot be perceived by color challenged individuals, for example blue, appear brighter. This system does not increase the incoming flux of any single color; it merely segregates a problematic spectrum from the overall spectrum to facilitate differential perception.
It would therefore be advantageous to provide a cosmetically acceptable, wearable device that increases the exposure of all or part of the human retina to beneficial wavelengths of light without requiring the use of bulky devices, power sources, or high-intensity fluxes. In particular, it would be advantageous to provide a solution that can be both subtractive and additive-converting nontherapeutic (or possibly even harmful) wavelengths into therapeutic, beneficial, or at the very least, nonharmful wavelengths.